1. Field of the Invention
The present invention relates to a flexible circuit board and its method for production method. More specifically, the invention relates to a flexible circuit board and a method for production thereof, in which the flexible circuit board can be used for connection between component parts which are mounted on various kinds of electronic equipment such as communication and visual equipment, etc., as well as automotive vehicles, aircrafts, robots, etc., or can be used for amounting circuit board with components mounted thereon, in particular for parts, such as movable parts of robots, etc., on which elasticity (expansion and contraction property) is required.
2. Description of Related Art
In recent years, development of robots is remarkable, and robots capable of performing a variety of motions are appearing. In addition, with respect to wearable electronic equipment which can be fitted or attached to a human body or clothing, a many variety of such equipment are developed. Many electric wires for supplying electric power or for transmitting signals are used in these robots and wearable electronic equipment, but in general, an electric wire is constructed such that it has a copper wire as a core, with its outer periphery covered by an insulating material, so the electric wire itself has almost no elasticity. For this reason, it is necessary to arrange an electric wire while providing a margin so as not to obstruct the motion of a robot or a human body, which becomes an obstacle to the design of devices and practical use in many cases.
Accordingly, in the past, there has been a demand for electric wires which are constructed to be elastic or expandable and contractable, in order to avoid such an obstacle to the design of devices as well as practical use. In particular, in equipment such as a front line humanoid type robot, a power assisted device which is worn or fitted on a human body so as to assist muscular power, many electric wires for operating end motors by way of multiple degree of freedom joints, respectively, and many electric wires for transmitting signals from various kinds of sensors arranged at end points are wired, and in order to enhance the degree of freedom of wiring in the multiple degree of freedom joints, the demand with respect to those electric wires which are constructed to be elastic or expandable and contractable is increasing more and more. Here, note that a related technique is disclosed in a first patent document, as listed below.